Short-stem Total Hip Arthroplasty Research Articles

Revision of Failed Short Stems in Total Hip Arthroplasty.

Background: The current literature lacks studies which evaluate the failure of short stems in total hip arthroplasty (THA). Therefore, the present clinical investigation reported our experience with the failure of short stems in THA, evaluating the causes of failure, survivorship, and the clinical outcomes of revision arthroplasty. Methods: The present study was performed according to the STROBE guidelines. This study was conducted at the Department of Orthopaedic Surgery of the Humanitas Clinical Institute, Milan, Italy, between 2017 and 2022. All patients who underwent revision surgery of a previously implanted THA using a short stem were prospectively included in the present study. Surgeries were performed with patients in lateral position, using a minimally invasive posterolateral approach. The outcomes of interest were to report information on the type and survivorship of implants used for the revision surgery and evaluate the clinical outcomes and the rate of complications. The following patient-reported outcome measures (PROMs) used for the clinical assessment were the Western Ontario McMaster Osteo-Arthritis Index (WOMAC) and related subscales of pain, stiffness, and function, and the visual analogue scale (VAS). Results: Data from 45 patients were retrieved. Of them, 31% (14 of 45 patients) were women. The mean age was 63.7 ± 13.9 years. The mean length of the implant survivorship was 6.2 ± 5.7 years. In total, 58% (26 of 45 patients) underwent revision of all components, 36% (16 of 45 patients) revised only the stem, and 1% (3 of 45 patients) received a two-stage revision. The mean length of the follow-up was 4.4 ± 1.5 years. The cup was revised in 58% (26 of 45) of patients. At 4.4 ± 1.5 years of follow-up, the WOMAC score was 3.5 ± 1.3 and the VAS was 1.2 ± 1.3. In total, 9% (4 of 45) of patients experienced minor complications. One patient used a walking aid because of reduced function. One patient evidenced muscular hypotrophy. Two patients experienced hip dislocations. All two dislocations were managed conservatively with repositioning in the emergency room under fluoroscopy. No patient needed additional revision surgery or experienced further dislocations. Conclusions: Revision surgery is effective and safe when a short stem THA fails. At approximately four years of follow-up, all patients were highly satisfied with their clinical outcomes. Despite the relatively high number (9%), complications were of a minor entity and were successfully managed conservatively.

Gender differences in cementless short stem total hip arthroplasty: significantly higher femoral lengthening in female patients

Modern cementless short stems in total hip arthroplasty (THA) enable a precise reconstruction of the native pre-arthritic hip geometry. While gender differences have been reported for older generation straight hip stems, there are hardly reports regarding modern cementless short hip stems. Therefore, we aimed to evaluate the influence of gender differences in hip anatomy in cementless short stem THA. A total of 207 patients (109 females, 98 males) with unilateral THA and absence of contralateral joint space narrowing (Kellgren-Lawrence grade ≤ 2) were included. Acetabular height and offset as well as femoral height and offset were measured on pre- and 3-months-postoperative anteroposterior X-rays of the pelvis and compared to the contralateral hip. Additionally, implant position was evaluated on the postoperative radiograph. In male patients, the loss of acetabular offset was significantly greater than in females (p = 0.012), leading to a compensatory increase in femoral offset (p = 0.041). Femoral height discrepancy was significantly higher in females (p < 0.001), accounting for an increased global hip height discrepancy (p < 0.001). The mean acetabular anteversion was significantly greater in female patients (p < 0.001). Female patients are at higher risk of femoral lengthening in THA with a cementless short stem potentially caused by a further proximally conducted femoral neck osteotomy and show significantly higher cup anteversion angles. Therefore, surgeons should take special care to the level of neck resection and implant positioning in female patients.

Prospective evaluation of clinical and radiographic 10-year results of Fitmore short-stem total hip arthroplasty

BackgroundShort stems were introduced into total hip arthroplasty (THA) to preserve bone stock, to transmit more load to the proximal femur, and to enable minimal invasive approaches. This study is the first long-term study (with a follow-up of 10 years) of the survival as well as the clinical and radiographic outcomes of the Fitmore hip stem, a short curved uncemented stem.MethodsIn total, 123 Fitmore hip stems were prospectively evaluated. At the final 10-year follow-up, 80 Fitmore stems (78 patients: 30 female, 48 male) were eligible for evaluation. Clinical parameters were thigh pain, EQ-5D, Harris Hip Score (HHS) and Oxford Hip Score. Radiographic parameters were cortical hypertrophy (CH), bone condensation, cortical thinning, radiolucency, reactive lines, calcar rounding, calcar resorption, subsidence and varus/valgus position.ResultsAfter 10 years, there was a survival rate of 99% (1 revision because of aseptic stem loosening). HHS had improved from 59 to 94 and Oxford Hip Score from 22 to 43. CH rate after 1 year was 69% and after 10 years 74%. In the first year, radiolucency was found in 58% and in 17.5% after 10 years. Subsidence after 1 year was 1.6 ± 1.6 mm and 5.0 ± 3.1 mm after 10 years.ConclusionsThe Fitmore hip stem showed a survival rate of 99% as well as good clinical and radiographic outcomes in the long-term follow-up of 10 years.

COMPARATIVE STUDY OF REVISION HIP ARTHROPLASTY AFTER SHORT STEM VERSUS AFTER CONVENTIONAL STEM

AbstractObjectiveShort-stem total hip arthroplasty (THA) aims to preserve the proximal bone stock for future revisions, so that the first revision should resemble a primary intervention rather than a revision. This study aimed to compare the clinical and radiological outcomes in revision THA after failed short stem versus after failed conventional stem THA.MethodsThis study included forty-five patients with revision THA divided into three groups (15 each); group A: revision after short stem, group B: revision after conventional cementless stem and group C revision after conventional cemented stem. The studied groups were compared regarding 31 variables including demographic data, details of the primary and revision procedures, postoperative radiological subsidence, hospital stay, time for full weight bearing (FWB), preoperative and postoperative clinical scores.ResultsEarly stem subsidence (40%) was the main indication of revision in group A compared to peri-prosthetic femoral fractures (PFFs) (73.3%) and aseptic loosening (53.3%) in group B and C respectively (P=0.021). The mean time to revision was significantly shorter in group A (15 months) compared to 95.33 and 189.40 months in group B and C respectively. (P=0.005). Sixty % (9 patients) in group A were revised in the first year. The mean operative time, blood loss, postoperative blood transfusion and hospital stay were significantly lower in group A compared to group B and C (P&lt;0.001, &lt;0.001, 0.002 and 0.001 respectively). Revisions in group A were performed using either short stems (13.3%) or conventional stems (86.7%) whilst 80% of patients needed long stems and 20% of patients needed conventional stems in group B and C (P&lt;0.001). The mean postoperative Harris Hip Score (HHS) at the latest follow up was 87.07, 87.53 and 85.47 in group A, B and C respectively. All PFFS had excellent results according to Beal's and Tower's criteria; all fractures healed and the implants were stable.ConclusionThe most common cause of failure of short stems is early stem subsidence. Short stem THA has specific indications and patient selection is very crucial. Preoperative templating for short stems and a detailed analysis of the individual patient anatomy in anteroposterior and lateral views are mandatory to predict the correct implant size more accurately. The use of intraoperative imaging can verify the sizing, implant position, and sufficient contact with the lateral cortex. Revision of short stem THA resembled the primary THA. If a standard implant can be used in a surgical revision instead of a longer revision stem, this can be considered as an advantage for the hip arthroplasty treatment concept. However, this only applies if the longevity of the first treatment with a short stem is comparable with that of a standard stem.Declaration of Interest(b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Short-stem total hip arthroplasty is equivalent to a standard-length stem procedure in an unselected population at mid-term follow-up.

Limitations of standard-length femoral stems persist, including proximal-distal mismatch, non-ideal load transfer, loss of bone tissue, and perioperative fracture. Symbol® (Dedienne Santé, France) is a metaphyseal-engaging short-stem implant designed to address these issues in total hip arthroplasty (THA). While short stems have been well studied in selected and younger patients, it is unclear whether they offer advantages in an unselected population. We hypothesized that short femoral stems offer similar mid-term survivorship at fiveyear minimum follow-up and function score to standard-length femoral stems, in an unselected patient population. We retrospectively reviewed a continuous unselected cohort of patients who undergone THA by one surgeon with a standard-length stem between November 2013 and October 2015, and a short stem between November 2015 and March 2017. We compared modified Harris Hip Score and Oxford Scores with a minimum follow-up of five years and procedural factors that could be associated with worse results with a short stem design. There was no difference in survival rate between the two groups. Average Harris Hip Score and Oxford Scores at the last follow-up were comparable. A multivariate linear regression was performed to assess the relationship between modified Harrys Hip Score at five years post-operatively and the explanatory variables: age, body mass index, physical status score ASA (American Society of Anesthesiologists), and HHS pre-op. None was associated with the standard-length stem but for the short stem. Short-stem implants provide good survival rate at mid-term; nevertheless, a steep learning curve is necessary to optimize the metaphyseal filling of the implant, especially for osteoporotic bone.

Short stem hip arthroplasty with the optimys prosthesis is a safe and effective option for obese patients: a mid-term follow-up multicenter study

IntroductionShort stems are a valuable option in young patients undergoing total hip arthroplasty (THA) because of their bone stock preserving properties facilitating revision hip arthroplasty. Although the effect of obesity on conventional THA is well studied, data about short stem THA in obese patients are lacking. Therefore, this study aimed to investigate the influence of obesity on complications, revisions, and outcome after short stem THA.Materials and methodsThis multicenter, observational cohort study included patients undergoing short stem THA with the optimys prosthesis. Follow-up examinations were performed at specific intervals up to 7 years postoperatively. Operation characteristics, general and specific complications, revisions, VAS rest pain, VAS load pain, VAS patient satisfaction, and Harris Hip Score (HHS) were recorded and statistically compared between obese (BMI ≥ 30 kg/m2) and non-obese (BMI < 30 kg/m2) patients.ResultsOf the 224 patients included with a mean follow-up of 87.2 months (range 81.9–104.0), 69 were assigned to the OB group and 155 to the non-OB group. A minimally invasive approach was significantly less often selected in obese patients (p = 0.049), whereas operating time and length of hospital stay were not significantly different. The rate of general and specific complications did not significantly differ between both groups. Survival of the optimys prosthesis was 99.1% at 7-year follow-up and one patient per group had to undergo revision surgery. VAS rest pain, load pain, and satisfaction improved from preoperatively to postoperatively in both groups without a significant difference between both groups. While the HHS was improved from preoperatively to postoperatively, obese patients showed a significantly lower HHS at the 7-year follow-up (p = 0.01) but still exhibited an excellent scoring above the PASS threshold.ConclusionShort stem THA with the optimys prosthesis is a safe and effective option also in obese patients with an excellent clinical outcome and a low complication rate.

Stem Design in Total Hip Arthroplasty Influences Ipsilateral Knee Valgus: A Retrospective Comparative Analysis of 2953 Cases.

Total hip arthroplasty (THA) affects the biomechanics of the hip and the patient gait. The stem design influences femoral lever ratios and tissue trauma. Biomechanical changes such as these have the potential to induce knee arthritis. A varus or valgus configuration of knee arthritis is formed by asymmetric loadings. The aim of this study was to evaluate the impact of stem design in THA on knee valgus by comparing a standard implant with an implant with a short stem. A total of 2953 patients who underwent primary total knee arthroplasty for end-stage osteoarthritis between 2015 and 2021 were included in this retrospective data analysis. Patients were divided into three groups, depending on hip status (straight stem, short stem, and native joint). Leg alignment was distinguished as varus or valgus, and the degree of axial deviation was measured. Descriptive and explorative statistical analyses were performed, with a p value < 0.05 set as significant. Ipsilateral knee valgus occurred significantly more often in patients with straight stems (57.2%) than in those with short stems (29%) and native joints (25.8%) (p < 0.001). Additionally, mean valgus deviation was significantly increased in patients with straight stems (8.9°) compared to those with short stems (6.4°) or native hip joints (6.7°). Both findings were accentuated in women. Previous ipsilateral straight-stem THA is associated with knee valgus deformity, especially in women. Short-stem THA seems to be better suited to restoring physiological biomechanics and preventing the development of valgus osteoarthritis of the ipsilateral knee.

Learning Curve for Short-Stem Total HIP Arthroplasty through an Anterolateral Approach.

Background and Objectives: Short-stem total hip arthroplasty has become increasingly popular in recent years. While many studies have shown excellent clinical and radiological results, very little is known about the learning curve for short-stem total hip arthroplasty through an anterolateral approach. Therefore, the aim of this study was to determine the learning curve for short-stem total hip arthroplasty among five residents in training. Materials and Methods: We performed retrospective data analysis of the first 30 cases of five randomly selected residents (n = 150 cases) with no experience before the index surgery. All patients were comparable, and several surgical parameters and radiological outcomes were analyzed. Results: The only surgical parameter with a significant improvement was the surgical time (p = 0.025). The changes in other surgical parameters and radiological outcomes showed no significant changes; only trends can be derived. As a result, the correlation between surgical time, blood loss, length of stay, and incision/suture time can also be seen. Only two of the five residents showed significant improvements in all examined surgical parameters. Conclusions: There are individual differences among the first 30 cases of the five residents. Some improved their surgical skills faster than others. It could be assumed that they assimilated their surgical skills after more surgeries. A further study with more than 30 cases of the five surgeons could provide more information on that assumption.

Simultaneous Bilateral Total Hip Arthroplasty with Straight-Stems and Short-Stems: Does the Short One Do a Better Job?

Total hip arthroplasty (THA) is known to be the most successful orthopaedic surgery of the last century, but it is still struggling with controversies concerning one-stage bilateral THA. The current study aimed to compare the clinical outcome of patients with unilateral or simultaneous bilateral THA by using short-stem and straight-stem designs and focusing on operation time, blood loss, and length of hospital stay (LOS). Between 2006 and 2018, 92 patients were enrolled in this study. Forty-six patients underwent a bilateral THA in one session, and forty-six matched patients underwent a unilateral THA. In each of the two groups (unilateral vs. bilateral), 23 patients received either a straight (unilateral: 10 females, 13 males, mean age 63; bilateral: 12 females, 11 males, mean age 53 years) or short stem (unilateral: 11 females, 12 males, mean age 60 years; bilateral: 12 females, 11 males, 53 mean age 62 years). The blood count was checked preoperatively as well as one and three days after surgery. Furthermore, the operation time and LOS were investigated. Compared to THA with straight-stems, short-stem THA showed significantly less blood loss; there was no difference in the LOS of both groups. A significantly shorter operative time was only observed in the bilateral THA. The current study showed that simultaneous bilateral THA appears to be safe and reliable in patients without multiple comorbidities. In addition, short-stem THA appears to be beneficial in terms of clinical performance and outcome, and it appears to be superior to straight-stem THA, regardless of whether the patient underwent unilateral or simultaneous bilateral THA.

A propensity score-matched analysis on the impact of patient and surgical factors on early periprosthetic joint infection in minimally invasive anterolateral and transgluteal total hip arthroplasty.

Increased risk of periprosthetic joint infection (PJI) in minimally invasive (MIS) total hip arthroplasty (THA) is still debated. This study aimed to identify differences in surgical and patient-related risk factors for PJI between an MIS anterolateral approach and transgluteal-modified Hardinge approach. A retrospective cohort of 5315 THAs performed between 2006 and 2019 at a single institution was screened. Short stem THAs performed via an MIS anterolateral approach in the supine position and standard straight stem THAs performed via a transgluteal modified Hardinge approach were included. Propensity score matching was performed to control for selection bias. After matching, 1405 (34.3%) short stem THAs implanted via MIS anterolateral approach and 2687 (65.7%) straight stem THAs implanted via a transgluteal modified Hardinge approach were included. The risk of PJI due to patient-specific and surgical factors was retrospectively analyzed using chi-square test and multivariate regression analysis. PJI occurred in 1.1% in both MIS anterolateral and transgluteal approach (p = 0.823). Multivariate regression showed an increased infection risk for patients with a BMI between 35 and 39.99kg/m2 (OR 6.696; CI 1.799-24.923; p = 0.005), which could not be demonstrated for transgluteal approach (OR 0.900; CI 0.900-4.144; p = 0.93). A BMI ≥ 40kg/m2 (OR 14.150; CI 2.416-82.879; p = 0.003) was detected as a risk factor for PJI only in anterolateral approach. Increased operation time ≥ 121min showed a significantly increased risk for PJI in the general cohort (OR 6.989; CI1.286-37.972; p = 0.024). Minimally invasive anterolateral and transgluteal THA show a comparable rate of early PJI within the first year of index surgery. A BMI of ≥ 35kg/m2 was detected as a clear risk factor for infection in the anterolateral approach. Prolonged operation time ≥ 121min increases the risk of PJI regardless of approach.

Periprosthetic Femoral Fractures in Cementless Short Versus Straight Stem Total Hip Arthroplasty: A Propensity Score Matched Analysis

BackgroundRecent studies indicate a decreased risk of periprosthetic femoral fractures (PFFs) in cementless total hip arthroplasty (THA) for short compared to straight stems. However, the results are still inconclusive. Therefore, we retrospectively investigated the rate of PFFs within the first year between cementless short and straight stem THA. MethodsA 1:1 propensity score matching of 3,053 THAs was performed. Two groups including 1,147 short stem THAs implanted through a minimally invasive antero-lateral approach and 1,147 straight stem THAs implanted through a transgluteal Hardinge approach were matched. The rates of PFFs and fracture patterns were compared between both stem types. Risk factors for PFFs were analyzed by multivariate regression analyses. ResultsThe overall rate of PFFs was 1.7% in short stem THA and 3.2% in straight stem THA (P = .015). Postoperatively detected Vancouver A fractures occurred significantly more often in straight stem THA (P = .002), while the occurrence Vancouver B fractures did not differ significantly (P = .563). The risk of PFFs was significantly increased for women in straight stem THA (Odds ratio (OR) 2.620; Confidence Interval (CI) 1.172-5.856; P = .019). Increasing age showed a significantly increased odds ratio in short stem (OR 1.103; CI 1.041-1.169, P < .001) and straight stem THA (OR 1.057; CI 1.014-1.101, P = .008). ConclusionShort stem THA reduces Vancouver Type A PFFs in the trochanteric region compared to straight stem THA, while Vancouver Type B fractures are comparable. Increasing age is a significant risk factor for both stem types, while the risk for PFFs in women was only significantly increased in the straight stem group.

Sexual activity after short-stem total hip arthroplasty. Does stem size matter?

BackgroundSexual activity is an important component of quality of life. To date, no studies have examined the impact of stem design on return to sexual activity (RTS) and quality of sex life after total hip arthroplasty (THA).MethodsA questionnaire was designed to assess preoperative and postoperative sexual habits, joint awareness and physical activity in working-age patients undergoing short-stem (n = 176) or straight-stem (n = 97) THA.ResultsNo differences were noted in time until RTS based on the stem design (short stems vs. straight stems; 6 [IQR: 4–10] vs. 6 [4–10] weeks; p = 0.996). Multivariate analysis revealed that higher patient BMI (p = 0.04), female gender (p < 0.001) and lower FJS-12 (p = 0.006) were significantly associated with delayed RTS. Improved hip mobility and reduced pain mainly contribute to improved quality of sexual activity postoperatively.ConclusionThis study, hence, indicates that stem design has no impact on time until resumption of sexual activity in patients < 65 years. Female obese individuals who are aware of their artificial joint in daily life are at increased risk of delayed RTS after surgery.Level of evidenceLevel III, retrospective cohort study.

Conversion of failed internal fixation in proximal femur fractures using calcar-guided short-stem total hip arthroplasty

PurposeReoperations for secondary osteoarthritis, osteonecrosis, or hardware failure following failed internal fixation after intertrochanteric fracture (ITF) or femoral neck fracture (FNF) are common. An effective salvage treatment often involves complete removal of the hardware followed by total hip arthroplasty (THA). Almost no data are available regarding conversion to short-stem THA. This study aimed to evaluate clinical and radiological outcomes, potential complications, and the survival rate of short-stem THA following revision surgery.MethodsWe investigated 27 patients who underwent conversion THA using a calcar-guided short stem. Patient-reported outcome measurements were obtained, including the Harris hip score, the Western Ontario and McMaster Universities Osteoarthritis Index, as well as pain and satisfaction on the visual analogue scale. Radiological follow-up was also performed.ResultsWe identified 18 (66.7%) patients diagnosed with FNF and 9 (33.3%) patients with ITF. Clinical and radiological outcomes were satisfactory at the last follow-up (30.56 ± 11.62 months). One patient required early revision surgery due to dislocation and greater trochanter fracture. At the last follow-up, none of the short stems required revision. No other major complications occurred.ConclusionGiven the low rate of complications and 100% survival, our findings indicate that short stems for conversion THA due to failed internal fixation may be considered an option in a properly selected patient population. However, it should not be considered a standard procedure and should only be performed by experienced surgeons.

Length doesn’t play a role – Sexual activity in men after short stem Total hip Arthroplasty

BackgroundChronic hip pain due to osteoarthritis or hip dysplasia has been shown to negatively affect many daily life aspects. One aspect, however, which persists underestimated is sexual health. The number of total hip arthroplasties (THA) are increasing, especially in young patients who have high functional expectations, not only to pain relief, but to an increase in hip mobility and quality of life as well as sexual activity.Aim(1) to report the demographic factors, (2) the sexual activity before and after THA, as well as the concerns related to sexual activity after THA and (3) the patient-reported outcome measurements (PROMs) in sexually active male patients.MethodsWe evaluated the results of patients between 18 and 65 years of age following primary cementless short femoral stem THA using a direct anterior approach (DAA) at a midterm follow-up of 4 years. A web-based questionnaire (via SurveyMonkey) was chosen to assess frequency, positions, complaints, fears, dealing with the questions and PROMs. Our patients sexual activity was via The Sexual Health Inventory for Men (SHIM) validated.ResultsPatients resumed their sexual activities after 6 weeks. The two main causes of difficulty in sexual activity before surgery were pain and limitation of the range of motion of the hip joint. Patients experienced less pain and an improvement in hip range of motion after THA. 89% of patients expressed a desire for more detailed and specific information on the subject. The patients foremost concern about muscle weakness, surgical scar or fear of dislocation. After 4 years follow-up our patients presented a significant improvement of the modified Harris Hip Score (mHHS) from 34.1 preoperative to 92.6 after THA.ConclusionTHA improves the quality in sexual life, in relation to less pain and improvement in the range of motion, but not in the frequency of sexual activity. Men’s sexual positions required less mobility and could therefore be considered safer.

Bone Preservation in Total Hip Arthroplasty.

Preserving bone stock in younger and more active patients after total hip arthroplasty (THA) is important for future revision. Newer prosthesis designs, including short femoral stems and isoelastic acetabular cups, are likely to preserve more bone stock. However, long-term follow-up studies on bone remodeling after short-stem THA with an isoelastic monoblock acetabular cup are few. Therefore, we evaluated bone preservation after THA using these prostheses at a 5-year follow-up. This prospective observational study is a 5-year follow-up of our previously reported 2-year observational study on the same cohort of patients. We included 45 patients with primary osteoarthritis treated with a calcar-guided femoral short-stem prosthesis and a monoblock press-fit acetabular cup. We evaluated bone mineral density (BMD) around the prostheses using dual-energy X-ray absorptiometry and reported functional outcomes preoperatively and at 3, 12, 24, and 60 months postoperatively. All complications were recorded. At the final follow-up, the BMD was comparable with that at 24 months in Gruen zones 3, 4, 5, 6, and 7, whereas it significantly differed in Gruen zones 1 (P < .0001) and 2 (P < .004). On the acetabular side, the BMD leveled off similarly in all DeLee and Charnley zones between 24 and 60 months (P > .05). Moreover, all measured clinical outcomes significantly improved (P < .001). One perioperative dislocation was reported. Patients undergoing THA with a calcar-guided femoral short-stem prosthesis and a monoblock acetabular cup can expect preservation of bone stock over a longer follow-up with excellent clinical outcomes and few complications.

Insufficient lateral stem contact is an influencing factor for significant subsidence in cementless short stem total hip arthroplasty.

BACKGROUNDSubsidence is one of the concerning early complications in cementless femoral stem. Few publications have studied the influencing factors for subsidence in short cementless stems, due to their metaphyseal anchoring without diaphyseal invasion, they might demonstrate different subsidence patterns than with the conventional stems.AIMTo analyze the factors associated with significant subsidence in short stems, including any radiographic parameters.METHODSThe digitized radiographs of 274 consecutive short stem total hip arthroplasties were retrospectively reviewed. Subsidence, neck-filling ratio (NFR), seating height and lateral stem contact were evaluated after a minimum of two years follow-up. A threshold of subsidence > 3 mm was considered a clinically significant migration.RESULTSFor the entire cohort, subsidence occurred in 75 cases (27.4%) with the mean stem subsidence of 0.5 mm. (0-12.7, 1.68). Twelve hips (4.4%) had significant subsidence (> 3 mm). The univariate regression analysis demonstrated that age, diagnosis, BMI, Dorr’s type B, NFR, and seating height had no significant influence on significant subsidence, whereas insufficient lateral stem contact (≥ 1 mm) did have a statistically significant influence [Odds ratio (OR) = 5.02; 95%CI: 1.3-18.9; P = 0.017]. The multivariate regression analysis also demonstrated that insufficient lateral stem contact was a statistically significant influencing factor (OR = 5.5; 95%CI: 1.4-21.4; P = 0.014). There was no femoral stem revision for aseptic loosening in our cohort.CONCLUSIONThis study demonstrated that insufficient lateral stem contact was a statistically significant influencing factor on significant subsidence. Therefore, it is a particularly important step to create proper lateral cortical contact when performing the short stem total hip arthroplasty.

Digital templating cementless short stem total hip arthroplasty: is there a difference in planning adherence between the direct anterior approach and minimally invasive anterolateral approach?

PurposeMinimally invasive approaches (MIS) in total hip arthroplasty (THA) show inconsistent findings regarding planning adherence in digital templating. The purpose of this study is to evaluate any difference in planning adherence between the direct anterior approach (DAA) and an anterolateral MIS approach (AL MIS) in cementless short stem THA.MethodsA single surgeon series of 222 THAs in 208 patients with an uncemented short curved stem and a bi-hemispherical acetabular cup were screened for inclusion. A total of 118 THAs were implanted via the DAA and 72 THAs via the AL MIS were included. The planning adherence for the offset option, stem size and the acetabular cup were retrospectively evaluated.ResultsPlanning adherence for cup size (perfect match: p = 0.763; ± 1 size: p = 0.124), offset option (0.125) and stem size (perfect match: p = 0.275; ± 1 size: p = 0.552) did not show any statistical significance. Preoperative diagnosis of avascular necrosis of the femoral head in AL MIS approach (OR 6.045; CI 1.153–31.696) or mild hip dysplasia in the general cohort poses (OR 11.789; CI 1.386–100.293) a significant risk for inadequate prediction of the offset option. Conclusion: digital templating for THA with an uncemented short curved stem and a bi-hemispherical acetabular cup show comparable results between a direct anterior approach and a minimally invasive anterolateral approach in supine position. Surgeons should be aware of a low planning adherence for this type of short stem in minimally invasive approaches.ConclusionDigital templating for THA with an uncemented short curved stem and a bi-hemispherical acetabular cup show comparable results between a direct anterior approach and a minimally invasive anterolateral approach in supine position. Surgeons should be aware of a low planning adherence for this type of short stem in minimally invasive approaches.

Cementless Short Stems in Total Hip Arthroplasty: Chances and Limits.

In recent decades, a large number of cementless short stems have been introduced to the market. The concept aims at saving soft tissue using minimally invasive surgery and at the same time preserving as much bone as possible. In particular, the latest generation of short stems, which are implanted using a calcar-guided round-the-corner technique, are attracting increasing attention. An individualised resection level allows individual stem alignment and thus an ideal reconstruction of the hip anatomy. The early clinical results of short-stem total hip arthroplasty (THA) are promising and have led to an expansion of the indications and limitations for the use of short stems. In particular, the individual positioning in valgus or varus and the resulting individual metaphyseal or metadiaphyseal anchorage offers various possibilities to reconstruct even abnormal joint morphologies. Consequently, short stems are increasingly used in patients with complex anatomical variations or in cases of osteonecrosis of the femoral head. In some various cases, they can also be used in revision or conversion arthroplasty. In some patients, short stems can also be used after femoral neck fracture. Currently, scientific data on those areas of indication of short-stem THA is scarce.

The ‘critical trochanter angle’ does not show superiority over the CCD angle in predicting varus stem alignment in cementless short-stem total hip arthroplasty

PurposeVarus positioning of the femoral stem can affect the hip offset (HO). The critical trochanter angle (CTA) was introduced in 2019 as a novel geometric angle, to predict varus stem alignment in cementless straight stem THA. The aim of this study was to evaluate the applicability of the CTA as a predictor for stem alignment in THA with a cementless neck resecting short stem.Patients and methodsIn this retrospective study, 106 patients (index surgery 2014–2019) with unilateral THA and a morphologically healthy contralateral hip as a reference (Kellgren–Lawrence ≤ 1) were included. A cementless short stem with meta-diaphyseal fixation and press-fit cup was implanted in all cases. Stem alignment, CCD angle, CTA and offset reconstruction were measured on preoperative and 3 months postoperative AP radiographs of the pelvis.ResultsPreoperative lower CTA and lower CCD angle were positively correlated (r = 0.472; p < 0.001). Higher varus stem alignment is correlated with lower CTA (r = − 0.384; p < 0.001) and lower CCD angle (r = − 0.474; p < 0.001). A CTA of 23.1° or lower showed a sensitivity of 59.1% and a specificity of 87.1% (AUC: 0.733) and a CCD angle of 132.75° or lower a sensitivity of 68.2% and a specificity of 80.6% (AUC: 0.77) for a varus stem alignment > 3°.ConclusionThe CTA is also applicable in cementless THA with a neck resecting short stem to evaluate risk of intraoperative varus stem positioning. The CCD angle shows higher sensitivity with marginally lower specificity. Therefore, the CTA is not superior in predicting varus stem alignment in short-stem THA.Level of evidence IV.

More than a feeling?—Overruling the preoperatively templated offset option leads to a minor offset increase in short stem total hip arthroplasty

PurposeShort stems are increasingly used in total hip arthroplasty (THA) because of advantages in bone and soft tissue preservation and reconstruction of hip geometry. Digital templating is essential in determining the correct offset option and stem size in THA. However, the preoperative template sizes might be intraoperatively overruled.Patients and methodsWe evaluated the effect of intraoperative overruling of the preoperatively templated offset option of a short curved stem on hip offset, leg length, implant positioning, and femoral canal fill index. The overruling was performed in case of intraoperative instability, telescoping, or both. A series of 1052 consecutive THAs with a cementless short curved stem and press-fit cup was retrospectively screened. One hundred patients with unilateral THA and a contralateral native and morphologically healthy hip as a reference met the inclusion criteria. Measurements were carried out on preoperative and 3 months anterior–posterior postoperative radiographs. Patients were divided according to the overruling by offset option or stem size.ResultsHip offset was increased in all groups, but only with significant increase if an offset option + 1 was used intraoperatively (p = 0.025). LLD was restored without significance in all groups (p = 0.323; p = 0.157).ConclusionIntraoperative overruling of the preoperative digital template in cementless short stem total hip arthroplasty results in an increase of hip offset compared to a contralateral healthy hip. However, the increase is marginal and clearly under 5 mm compared to the contralateral healthy hip.